• Title/Summary/Keyword: memory assignment

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Real-time Optimization of H.264 Software Encoder on Embedded DSP System (임베디드 DSP 기반 시스템을 위한 H.264 소프트웨어 부호기의 실시간 최적화)

  • Roh, Si-Bong;Ahn, Hee-June;Lee, Myeong-Jin;Oh, Hyuk-Jun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.10C
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    • pp.983-991
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    • 2009
  • While H.264/AVC is in wide use for multimedia applications such as DMB and IPTV service, we have limited usage cases for embedded real-time applications due to its high computational demand. The paper provides judicious guide line for optimization method selection, by presenting the detailed experiments data through the development process of a real time H.264 software encoder on embedded DSP. The experimental analysis includes an intensive profiling analysis, fast algorithm application, optimal memory assignment, and intrinsic-based instruction selection. We have realized a real-time software that encodes CIF resolution videos 15 fps on TMS320DM64x processors.

The Effects of Instruction using the e-Learning in ‘Geological’ Unit of Middle School Science on Long and Short Term Retention (중학교 과학 ‘지질’ 영역에서 e-Learning 활용 수업이 장·단기 파지에 미치는 효과)

  • Lee, Chai-Eung;Lee, Yong-Seob;Kim, Sang-Dal
    • Journal of the Korean earth science society
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    • v.26 no.6
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    • pp.469-476
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    • 2005
  • The objective of this study is to investigate the effects of a new learning method called, 'e-Learning,' by applying this method on a middle school science curriculum and study the influence it has on the students’ short and long term memory. The study was performed on two classes of sixth grade students at 'K middle school' in Yangsan. By handing out structured study assignment in e-Learning, I was able to observe how it affected the learners’ short and long term retention. The results of the study were as follows: First, classes that underwent studies using e-Learning did not show any influence on short term retention. Second, e-Learning had positive influence on long term retention. Third, learners who experienced e-Learning had positive cognition on e-Learning.

A Resource-Aware Mapping Algorithm for Coarse-Grained Reconfigurable Architecture Using List Scheduling (리스트 스케줄링을 통한 Coarse-Grained 재구성 구조의 맵핑 알고리즘 개발)

  • Kim, Hyun-Jin;Hong, Hye-Jeong;Kim, Hong-Sik;Kang, Sung-Ho
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.6
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    • pp.58-64
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    • 2009
  • For the success of the reconfigurable computing, the algorithm for mapping operations onto coarse-grained reconfigurable architecture is very important. This paper proposes a resource-aware mapping system for the coarse-grained reconfigurable architecture and its own underlying heuristic algorithm. The operation assignment and the routing path allocation are simultaneously performed with a cycle-accurate time-exclusive resource model. The proposed algorithm minimizes the communication resource usage and the global memory access with the list scheduling heuristic. The operation to be mapped are prioritized with general properties of data flow. The evaluations of the proposed algorithm show that the performance is significantly enhanced in several benchmark applications.

On the Performance of Sample-Adaptive Product Quantizer for Noisy Channels (표본적응 프러덕트 양자기의 전송로 잡음에서의 성능 분석에 관한 연구)

  • Kim Dong Sik
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.42 no.3 s.303
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    • pp.81-90
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    • 2005
  • When we transmit signals, which are quantized by the vector quantizer (VQ), through noisy channels, the overall performance of the coding system is very dependent on the employed quantization scheme and the channel error effect. In order to design an optimal coding system, the source and channel coding scheme should be jointly optimized as in the channel-optimized VQ. As a suboptimal approach, we may consider the robust VQ (RVQ). In RVQ, we consider developing an index assignment function for mapping the output of quantizers to channel symbols so that the effect of the channel errors is minimized. Recently, a VQ, which can reduce the encoding complexity and is called the sample-adaptive product quantizer (SAPQ), has been proposed. SAPQ has very similar quantizer structure as to the product quantizer (PQ). However, the quantization performance can be better than PQ. Further, the encoding complexity and the memory requirement for the codebooks are lower than the regular full-search VQ case. In this paper, SAPQ is employed in order to design an RVQ to channel errors by reducing the vector dimension. Discussions on the codebook structure of SAPQ and experiments are introduced in an aspect of robustness to noisy channels.

Design and Implementation of the Central Queue Based Loop Scheduling Method (중앙 큐 기반의 루프 스케쥴링 기법의 설계 및 구현)

  • Kim, Hyun-Chul;Kim, Hyo-Cheol;Yoo, Kee-Young
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.38 no.5
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    • pp.16-26
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    • 2001
  • In this paper, we present a new scheduling method called CDSS(Carried-Dependence Self-Scheduling) for efficiently execution of the loop with intra dependency between iterations based on the central queue. We also implemented it on shared memory system using Java language. Also, we study the modification that converts the existing self-scheduling method based on the central task queue for parallel loops onto the same form applied to loop with loop-carried dependences. The proposed method is self scheduling and assigns the loops in three-level considering the synchronization point according to the dependence distance of the loops. To adapt the proposed scheme and modified methods into various platforms, including a uni-processor system, we use threads for implementation. Compared to other assignment algorithms with various changes of application and system parameters, CDSS is found to be more efficient than other methods in overall execution time including scheduling overheads. CDSS shows improved performance over modified SS, Factoring, GSS and CSS by about 0.02, 40.5, 46.1 and 53.6%, respectively. In CDSS, we achieve the best performance on varying application programs using a few threads, which equal the dependence distance.

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A Folksonomy Ranking Framework: A Semantic Graph-based Approach (폭소노미 사이트를 위한 랭킹 프레임워크 설계: 시맨틱 그래프기반 접근)

  • Park, Hyun-Jung;Rho, Sang-Kyu
    • Asia pacific journal of information systems
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    • v.21 no.2
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    • pp.89-116
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    • 2011
  • In collaborative tagging systems such as Delicious.com and Flickr.com, users assign keywords or tags to their uploaded resources, such as bookmarks and pictures, for their future use or sharing purposes. The collection of resources and tags generated by a user is called a personomy, and the collection of all personomies constitutes the folksonomy. The most significant need of the folksonomy users Is to efficiently find useful resources or experts on specific topics. An excellent ranking algorithm would assign higher ranking to more useful resources or experts. What resources are considered useful In a folksonomic system? Does a standard superior to frequency or freshness exist? The resource recommended by more users with mere expertise should be worthy of attention. This ranking paradigm can be implemented through a graph-based ranking algorithm. Two well-known representatives of such a paradigm are Page Rank by Google and HITS(Hypertext Induced Topic Selection) by Kleinberg. Both Page Rank and HITS assign a higher evaluation score to pages linked to more higher-scored pages. HITS differs from PageRank in that it utilizes two kinds of scores: authority and hub scores. The ranking objects of these pages are limited to Web pages, whereas the ranking objects of a folksonomic system are somewhat heterogeneous(i.e., users, resources, and tags). Therefore, uniform application of the voting notion of PageRank and HITS based on the links to a folksonomy would be unreasonable, In a folksonomic system, each link corresponding to a property can have an opposite direction, depending on whether the property is an active or a passive voice. The current research stems from the Idea that a graph-based ranking algorithm could be applied to the folksonomic system using the concept of mutual Interactions between entitles, rather than the voting notion of PageRank or HITS. The concept of mutual interactions, proposed for ranking the Semantic Web resources, enables the calculation of importance scores of various resources unaffected by link directions. The weights of a property representing the mutual interaction between classes are assigned depending on the relative significance of the property to the resource importance of each class. This class-oriented approach is based on the fact that, in the Semantic Web, there are many heterogeneous classes; thus, applying a different appraisal standard for each class is more reasonable. This is similar to the evaluation method of humans, where different items are assigned specific weights, which are then summed up to determine the weighted average. We can check for missing properties more easily with this approach than with other predicate-oriented approaches. A user of a tagging system usually assigns more than one tags to the same resource, and there can be more than one tags with the same subjectivity and objectivity. In the case that many users assign similar tags to the same resource, grading the users differently depending on the assignment order becomes necessary. This idea comes from the studies in psychology wherein expertise involves the ability to select the most relevant information for achieving a goal. An expert should be someone who not only has a large collection of documents annotated with a particular tag, but also tends to add documents of high quality to his/her collections. Such documents are identified by the number, as well as the expertise, of users who have the same documents in their collections. In other words, there is a relationship of mutual reinforcement between the expertise of a user and the quality of a document. In addition, there is a need to rank entities related more closely to a certain entity. Considering the property of social media that ensures the popularity of a topic is temporary, recent data should have more weight than old data. We propose a comprehensive folksonomy ranking framework in which all these considerations are dealt with and that can be easily customized to each folksonomy site for ranking purposes. To examine the validity of our ranking algorithm and show the mechanism of adjusting property, time, and expertise weights, we first use a dataset designed for analyzing the effect of each ranking factor independently. We then show the ranking results of a real folksonomy site, with the ranking factors combined. Because the ground truth of a given dataset is not known when it comes to ranking, we inject simulated data whose ranking results can be predicted into the real dataset and compare the ranking results of our algorithm with that of a previous HITS-based algorithm. Our semantic ranking algorithm based on the concept of mutual interaction seems to be preferable to the HITS-based algorithm as a flexible folksonomy ranking framework. Some concrete points of difference are as follows. First, with the time concept applied to the property weights, our algorithm shows superior performance in lowering the scores of older data and raising the scores of newer data. Second, applying the time concept to the expertise weights, as well as to the property weights, our algorithm controls the conflicting influence of expertise weights and enhances overall consistency of time-valued ranking. The expertise weights of the previous study can act as an obstacle to the time-valued ranking because the number of followers increases as time goes on. Third, many new properties and classes can be included in our framework. The previous HITS-based algorithm, based on the voting notion, loses ground in the situation where the domain consists of more than two classes, or where other important properties, such as "sent through twitter" or "registered as a friend," are added to the domain. Forth, there is a big difference in the calculation time and memory use between the two kinds of algorithms. While the matrix multiplication of two matrices, has to be executed twice for the previous HITS-based algorithm, this is unnecessary with our algorithm. In our ranking framework, various folksonomy ranking policies can be expressed with the ranking factors combined and our approach can work, even if the folksonomy site is not implemented with Semantic Web languages. Above all, the time weight proposed in this paper will be applicable to various domains, including social media, where time value is considered important.